Windows Tutorials - Herong's Tutorial Examples - Version 5.62, by Dr. Herong Yang
Glossary of Terms
Glossary of terms used in this book.
BMP (Bitmap): A graphics file format used by MS Windows systems. It has no compression.
DOS (Disk Operating System): An operating system that resides on a disk. This term commonly refers to a group of similar operating systems for the IBM-compatible personal computer, including MS-DOS, PC-DOS, DR-DOS, and FreeDOS
FTP (File Transfer Protocol): An Internet protocol that allows users to transfer files from and to remote computers.
JPG/JPEG (Joint Photographic Experts Group): Pronounced as "jay-peg". JPEG (pronounced jay-peg) is a commonly used standard method of lossy compression for photographic images. The file format which employs this compression is commonly also called JPEG; the most common file extensions for this format are .jpeg, .jfif, .jpg, .JPG, or .JPE although .jpg is the most common on all platforms.
The name stands for Joint Photographic Experts Group. JPEG itself specifies only how an image is transformed into a stream of bytes, but not how those bytes are encapsulated in any particular storage medium. A further standard, created by the Independent JPEG Group, called JFIF (JPEG File Interchange Format) specifies how to produce a file suitable for computer storage and transmission (such as over the Internet) from a JPEG stream. In common usage, when one speaks of a "JPEG file" one generally means a JFIF file, or sometimes an Exif JPEG file. There are, however, other JPEG-based file formats, such as JNG, and the TIFF format can carry JPEG data as well.
JPEG/JFIF is the most common format used for storing and transmitting photographs on the World Wide Web. It is not as well suited for line drawings and other textual or iconic graphics because its compression method performs badly on these types of images (the PNG and GIF formats are in common use for that purpose; GIF, having only 8 bits per pixel is not well suited for colour photographs, PNG can be used to losslessly store photographs but the filesize makes it largely unsuitable for putting photographs on the web).
GIF (Graphics Interchange Format): A bitmap image format for pictures that use 256 (or fewer) distinct colors (though there is a workaround for this limitation) and animations that use 256 (or fewer) distinct colors per frame. GIFs are compressed files, and are employed specifically to reduce the amount of time it takes to transfer images over a network connection. The format was introduced by CompuServe in 1987 and has since come into widespread usage on the World Wide Web.
A GIF file employs lossless data compression so that the file size of an image may be reduced without degrading the visual quality (provided the image fits into 256 colors). The GIF format's 256-color limitation makes it unsuitable for photographs, though losslessly compressed photographs tend to be unacceptably large for the web anyway. On the other hand the lossy JPEG format does badly on sharp transitions like those in diagrams, producing highly visible artifacts and little file-size reduction. Therefore GIF is normally used for diagrams, buttons, etc., that have a small number of colors, while the JPEG format is used for photographs.
GUI (Graphical User Interface): Pronounced as "gooey". GUI is a method of interacting with a computer through a metaphor of direct manipulation of graphical images and widgets in addition to text.
IP (Internet Protocol) Address: An identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the IP address of the destination. The format of an IP address is a 32-bit numeric address written as four numbers separated by periods. Each number can be zero to 255. For example, 184.108.40.206 could be an IP address.
PIXEL (Picture Element): Short for Picture Element, a pixel is a single point in a graphic image. Graphics monitors display pictures by dividing the display screen into thousands (or millions) of pixels, arranged in rows and columns. The pixels are so close together that they appear connected.
The number of bits used to represent each pixel determines how many colors or shades of gray can be displayed. For example, in 8-bit color mode, the color monitor uses 8 bits for each pixel, making it possible to display 2 to the 8th power (256) different colors or shades of gray.
On color monitors, each pixel is actually composed of three dots -- a red, a blue, and a green one. Ideally, the three dots should all converge at the same point, but all monitors have some convergence error that can make color pixels appear fuzzy.
The quality of a display system largely depends on its resolution, how many pixels it can display, and how many bits are used to represent each pixel. VGA systems display 640 by 480, or about 300,000 pixels. In contrast, SVGA systems display 800 by 600, or 480,000 pixels. True Color systems use 24 bits per pixel, allowing them to display more than 16 million different colors.
RAR (Roshal Archive): RAR is a proprietary file format for data compression and archiving. The RAR format was developed by Eugene Roshal (hence the name RAR: Roshal ARchive), who was born on March 10, 1972 in Russia and graduated from Chelyabinsk Technical University. He also developed programs for packing and unpacking RAR files, originally for DOS, and later ported to other platforms. The encoder (the main Windows version known as WinRAR) is distributed as shareware, but Roshal has released the decoder's source code under a license that allows free distribution and modification, on condition that it is not reverse-engineered to build a compatible encoder. The encoding method is held to be proprietary, but compatible programs for decompression are available for several platforms, such as the open-source 7-Zip.
Spyware: Spyware is a broad category of malicious software designed to intercept or take partial control of a computer's operation without the informed consent of that machine's owner or legitimate user. While the term taken literally suggests software that surreptitiously monitors the user, it has come to refer more broadly to software that subverts the computer's operation for the benefit of a third party.
Spyware differs from viruses and worms in that it does not usually self-replicate. Like many recent viruses, however, spyware is designed to exploit infected computers for commercial gain. Typical tactics furthering this goal include delivery of unsolicited pop-up advertisements; theft of personal information (including financial information such as credit card numbers); monitoring of Web-browsing activity for marketing purposes; or routing of HTTP requests to advertising sites.
TCP (Transmission Control Protocol): One of the core protocols of the Internet protocol suite. Using TCP, applications on networked hosts can create connections to one another, over which they can exchange data. The protocol guarantees reliable and in-order delivery of sender to receiver data. TCP also distinguishes data for multiple, concurrent applications (e.g. Web server and email server) running on the same host
ZIP: A file format is a popular data compression and archival format. A ZIP file contains one or more files that have been compressed or stored.
The format was originally designed by Phil Katz for PKZIP. However, many software utilities other than PKZIP itself are now available to create, modify or open ZIP files, notably WinZip, BOMArchiveHelper, PicoZip, Info-ZIP, WinRAR and 7-Zip. Microsoft has also included minimal ZIP support (under the name "compressed folders") in later versions of its Windows operating system.
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